The behaviors which develop in school are not only intellectual or academic achievement ones; for example, social skills and self- esteem develop. In turn, individual organismic variables other than those that are cognitive (for example, pubertal level, physical attractiveness, and temperament) provides bases of intellectual developments, academic achievements, and those social and personality characteristics which develop within the school. The early adolescent period is an essential time within which to study the non-intellective bases of school behaviors and achievements. First, there is empirical knowledge that some of these variables change in early adolescence (e.g., pubertal change, of course, occurs), and there is theoretical reason to expect changes in others (e.g., mood, activity level). Moreover, there may be interactions among these changes (e.g., particular pubertal changes may influence attractiveness). Second, the differential contributions of non-intellective variables to school behaviors and achievements can best be studied when the system of student-school relations is in the process of organization as compared to when the system is firmly established. It is ideal, then, to study the early adolescent's transition to junior high school because it involves students moving from one setting, where they have been enrolled for several years, to another one, requiring learning new rules and establishing new social and academic relations. However, no study has as yet longitudinally investigated the contribution of the above-noted non-intellective variables to early adolescents' school behaviors and achievements. What is needed is longitudinal research assessing non-intellective and theoretically-relevant personality, social, and academic variables, and spanning the transition to junior high school. To provide such data we request four years of support. Year One is devoted to: (a) organizing and analyzing data present in a recently (May 1986) completed, short- term longitudinal study of early adolescent transitions; and (b) beginning to collect data from the first of three new cohorts of early adolescents who will become the sample of a new, short-term longitudinal study designed to cross-validate and extend some of the results in the previous study. In years 2 to 4 we will assess the second and third cohorts and will engage in data base organization and analysis of the new longitudinal data.